Germanium selenide is a member of the chalcogenide class of compounds. Films of these compounds have been used in the manufacture of computer memory devices. Memory densities in excess of 340 Mbits/cm2 have been demonstrated with germanium selenide films with a minimum single layer feature size of approximately 0.18 micrometers.
Chalcogenides are finding utility in the manufacture of programmable metallization cells which have the potential for playing a significant role in future generations of computer memories. Thus, efficient formation of germanium selenide films with known and reproducable stoichiometries is an important goal. Germanium selenide films are typically formed by co-sputtering pure germanium and pure selenium targets. Simultaneous sputtering of both targets is carried out with simultaneous deposit of Ge and Se onto a common substrate, thereby creating a film containing both germanium and selenium
However, the co-sputtering formation of germanium selenide films requires complex sputtering equipment, increasing processing costs. Also, precise control of two separate sputtering processes to achieve adequate film homogeneity, film uniformity, and film stoichiometry. Achieving such objectives in a production environment, as opposed to a laboratory environment, presents a significant and costly challenge.